What is the sea turtle mount in World of Warcraft?

The sea turtle is a rare mount obtained from the fishing pools of Northrend, select cataclysm-level pools and Pandaria. Its appearance is that of a massive sea turtle with green shell and bluish-tinted skin.

This mount is very rare and takes significant time in finding for the average player. As it's purely a random drop, there is no set time of how long it takes to find; however, drop rates, as of 2014, are around once per every 5,000 fishing attempts. Upon looting of the sea turtle mount, players are granted the achievement "Turtles All the Way Down" and can never get a second turtle.